<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        let p = new Promise((resolve, reject)=>{
            resolve('ok')
        })

        p.then(value => {
            console.log(111)
            return new Promise(()=>{})
        }).then(value=>{
            console.log(222)
        }).then(value=>{
            console.log(333)
        }).catch(reason => {
            console.warn(reason)
        })
    </script>
</body>
</html>